To get this stay of execution, file Form 4868. You can fill it out and file it electronically through the IRS Free File program, freefile.irs.gov, a partnership between the IRS and private tax-preparation companies. Several participants provide free e-filing of extension requests, regardless of income.

Alternatively, you can print out a copy of Form 4868 and mail it to the IRS. Just make sure it's postmarked April 17 to avoid late filing penalties. Once you've e-filed or mailed your extension request, you have until Oct. 15 to file your return.

Procrastination isn't the only reason millions of taxpayers file for an extension every year. Some ask for more time to file because they haven't received all of the documents they need to prepare their taxes. Betsey Buckingham, an enrolled agent in Dayton, Ohio, says she's filing an extension for a client who hasn't received a K-1, a document that reports income from a partnership. In such cases, she says, filing for an extension is less expensive and time-consuming than filing an amended return.

Republican presidential candidate Mitt Romney announced on Friday that he, too, has filed for an extension on his 2011 tax return. In a statement, spokeswoman Andrea Saul said Romney requested the extension because he doesn't have all the information he needs to file by April 17.

No break on payments

Except in limited circumstances, filing for an extension doesn't give you more time to pay your taxes.

If you owe money to the IRS, you should estimate your tax bill and include payment when you file your extension, the IRS says. The IRS accepts credit cards, although you'll have to pay a "convenience fee" of 1.89% to 3.93% of your payment.

Taxpayers who have no cash or credit with which to pay the IRS should still file Form 4868 by midnight, Buckingham says. You'll owe interest and penalties on the unpaid balance, but you'll avoid the more punitive failure-to-file penalty of 5% per month of your unpaid balance, up to 25% of the amount you owe, she says.

Some taxpayers have more time to file and pay their taxes without having to request an extension. They include:

Taxpayers who are out of the country on April 17. Those individuals have until June 15 to file and pay their taxes. However, interest will accrue on the unpaid balance after April 17. If you're out of the country, make sure you can document your whereabouts on April 17 in case the IRS has questions.

Members of the military who are serving in Iraq, Afghanistan or other combat zones. Those individuals typically have 180 days after they leave the combat zone to file and pay any taxes due. For more information, see IRS Publication 3, Armed Forces Tax Guide.

Individuals and businesses in areas damaged by recent tornadoes, floods and natural disasters have until May 31 to file and pay. Affected areas include parts of Indiana, Kentucky, Tennessee and West Virginia covered by federal disaster declarations, the IRS says. Go to fema.gov or to irs.gov and search under "Tax Relief in Disaster Situations" for more info

Scam alert

If you file for an extension and are due a refund, the IRS will gladly hold on to your money until you get your act together. But waiting to claim your refund could expose you to a rapidly growing identity theft scam. Tax-related fraud accounted for nearly a quarter of identity theft complaints in 2011, up from 13% in 2009, according to the Federal Trade Commission.

Armed with stolen Social Security numbers, identity thieves have filed thousands of fraudulent tax returns and collected millions in refunds.

Taxpayers usually don't realize their identities have been stolen until they try to file and have their return rejected by the IRS. Some victims have had to wait months for their refunds while the IRS investigated the fraud.

The longer you wait to file, the more time crooks have to steal your identity and hijack your refund.

For more information, go to irs.gov and search under "Taxpayer Guide to Identity Theft."